Trigg Bushland has the privilege of having the largest, healthiest and most natural stand of the Rottnest Island Pine of any bush reserve within the Perth metropolitan region. Traveling north on West Coast Highway, this special grove of dark green, neatly oval trees up to 9m in height can be seen along the high dune crests just to the east of Trigg Beach. Even better, a path leads into the grove; stop and have a look. Other locations include Rottnest Island, Garden Island, scattered trees in other coastal city bush reserves and street plantings, especially along Marmion Avenue just south of the Reid Highway intersection. Now confined to scattered remnants or isolated stands, this species’ natural distribution once stretched from north of Shark Bay through the Swan Coastal Plain to mallee country north of Ravensthorpe and Esperance.
We all must ensure the conservation of the remaining small forests of Rottnest Island Pine (Callitris preissii) at all costs. Although the trees are tough, long living survivors, they have a natural and inherent weakness. They are killed by bushfires and it is only the seed, shed during that destructive fire, that perpetuates the species. The trees never resprout and another 10 to 15 years will pass before a new generation of Rottnest Island Pine trees may be sufficiently mature to create their own seed stock. Increasing maturity is the only criterion that ensures a sufficient seed stock in the soil for future generations. So, conservationists recommend that to conserve just this one unique coastal WA species there should be no burning of bushland of any sort for at least 20 to 30 years.
That time span is calculated and recommended by fire specialist biologists as the age of the tree when it first produces seed multiplied by two and a half to three and a half times. Trouble is, we have no idea how old the Trigg Bushland natural stand is. The last bushfire that very nearly destroyed Trigg’s Rottnest Island Pines occurred on Monday 14 th December 1998. Do you remember it? That means that the youngest trees in the grove could be seedlings that germinated as a result of this fire. They are not quite 10 years old and will not have reached seed bearing status. Another 5 to 15 years, without fire, are necessary before these trees will reach some sustainable maturity.
The Rottnest Island Pine does not produce flowers, fruit and seed like, say the Eucalypts. Instead, like conifers and the cypress, each tree produces female cones and male sporangial clusters. In spring, the latter form as the tiny golden tips along special short branches within the green crown so that the trees take on a golden hue. The green of these branches comes from minute leaves closely adpressed to each soft stem. The pollen is distributed by wind. The female cones arise from the woody branches and are large, black and warty. They shed black nutty seeds in late summer, though copious seed is released during a fire and the seeds germinate best after fire followed by rain.
More information about Threatened Ecological Communites from the DPaW website.
DPaw Interim Recovery Plan for Threatened Ecological Community (TEC) SCP30a – Callitris preissii.
Notification Report for new Bush Forever Site 308 TEC SCP30a.
Media coverage of new TEC in South Trigg Bushland – here.